Bruzik J P, Maniatis T
Case Western Reserve University, Department of Molecular Biology and Microbiology, Cleveland, OH 44106, USA.
Proc Natl Acad Sci U S A. 1995 Jul 18;92(15):7056-9. doi: 10.1073/pnas.92.15.7056.
Splice-site selection and alternative splicing of nuclear pre-mRNAs can be controlled by splicing enhancers that act by promoting the activity of upstream splice sites. Here we show that RNA molecules containing a 3' splice site and enhancer sequence are efficiently spliced in trans to RNA molecules containing normally cis-spliced 5' splice sites or to normally trans-spliced spliced leader RNAs from lower eukaryotes. In addition, we show that this reaction is stimulated by (Ser + Arg)-rich splicing factors that are known to promote protein-protein interactions in the cis-splicing reaction. Thus, splicing enhancers facilitate the assembly of protein complexes on RNAs containing a 3' splice site, and this complex is sufficiently stable to functionally interact with 5' splice sites located on separate RNAs. This trans-splicing is mediated by interactions between (Ser + Arg)-rich splicing factors bound to the enhancer and general splicing factors bound to the 5' and 3' splice sites. These same interactions are likely to play a crucial role in alternative splicing and splice-site selection in cis.
核内前体mRNA的剪接位点选择和可变剪接可由剪接增强子控制，这些增强子通过促进上游剪接位点的活性来发挥作用。在此我们表明，含有3'剪接位点和增强子序列的RNA分子能有效地与含有正常顺式剪接的5'剪接位点的RNA分子或与来自低等真核生物的正常反式剪接的剪接前导RNA进行反式剪接。此外，我们还表明，这种反应受到富含（丝氨酸+精氨酸）的剪接因子的刺激，已知这些因子在顺式剪接反应中促进蛋白质-蛋白质相互作用。因此，剪接增强子有助于在含有3'剪接位点的RNA上组装蛋白质复合物，并且这种复合物足够稳定，能够与位于不同RNA上的5'剪接位点进行功能相互作用。这种反式剪接是由与增强子结合的富含（丝氨酸+精氨酸）的剪接因子和与5'及3'剪接位点结合的一般剪接因子之间的相互作用介导的。这些相同的相互作用可能在顺式可变剪接和剪接位点选择中起关键作用。
